(a) Field of the Invention
The invention relates to a constant temperature sealed cooking device, and more particularly, to a novel structure providing a conventional sealed cooking device with constant temperature effects. The constant temperature sealed cooker is devised with a constant temperature generating apparatus at an inner lower portion of a heat resistant outer pot thereof. Using the constant temperature generating apparatus, a constant temperature within an inner pot is maintained.
(b) Description of the Prior Art
According to a common sealed cooker, an inner pot is heated by fire and placed into an interior of a sealed cooker. Using thermal insulation properties of the sealed cooker, food contained therein is continuously heated and cooked by the heat produced, thereby accomplishing purposes of economizing gas or electric power. Positive cooking effects are thus obtained as the food needs to be cooked to a certain degree. As a forerunner of a sealed cooker, an electric cooker or a gentle fire that cooks food in a method of gradual stewing offers specific tastes to the food prepared. Furthermore, nutrients of the food being prepared by an 80-degree Celsius remain undamaged, and therefore development of sealed cookers has beneficial effects regarding to resources and cuisine. However, conventional sealed cookers are prone to temperature lowering, and hence cooked degrees of food vary due to insufficient temperature. Food like meat requires a temperature over 80-degrees Celsius and rather lengthy sealed heating in order to be completely and thoroughly cooked. Also, for that sizes of individual pieces of meat may be different, time needed for sealed heating may be unequal too. Again, according to different sizes of the meat, it is likely that center portions of particular pieces are not entirely cooked when using a conventional sealed cooker because a temperature needed for thoroughly cooking the center portion is around 80 degrees Celsius, thereby creating different tastes relative to individual pieces of the meat. Amounts of heat accepted by various foods with different textures differ as well. For example, fats, proteins, fibers and vegetables, all need different amounts of heat to be completely cooked. Based on distinct heat resistance of various kinds of food, textures of food may be destructed for those that are non-endurable to continuous heating. In Chinese cuisine, because different kinds of food are cooked in a same pot, cooked degrees of the foods are consequently different as well. Therefore, for a dish well prepared in a same pot, it is essential to place different food according to appropriate orders. For example, meat that needs to be cooked with a longer period is simmered first, whereas food like vegetables or proteins that are easily cooked is placed into the pot in subsequent complementary steps. Yet, for a conventional sealed cooker in order to complete the subsequent complementary steps, a lid thereof is necessarily opened. As a result, heat therein is substantially dissipated to lower a cooked degree of the meat, and thereby failing to satisfy ideal cuisine. Thus, applications of conventional sealed cookers cannot be extensively adopted for all kinds of dishes.
Referring to FIG. 1 showing a temperature lowering curve of a conventional sealed cooker, when food is placed in the sealed pot after an inner pot thereof has reached a boiling point, only a temperature of approximately 95 degrees Celsius is remained, and the temperature further drops to 70 degrees Celsius at the 7th hour. The curve drops direct proportionally, meaning that a temperature valid for cooking the meat only lasts for about three and half hours. In addition, for that pieces of meat come in various sizes, not all center portions of all pieces of meat can be thoroughly cooked within three and half hours. After three and half hours, the temperature is dropped to below 80 degrees Celsius. It then becomes probable that the pieces of meat are not completely cooked and may be unevenly cooked as well. For ribs stewed in sauces, a temperature below 80 degrees Celsius is hardly able to bring out nutrients in the marrow of bones, and a broth made may not have a deserved taste.